Hydraulic cylinder device



Feb. 9, 1965 R. PRINCE 3,163,853

HYDRAULIC CYLINDER DEVICE Filed Oct. 8, 1962 2 Sheelzs--SheerI 1 f f mw H wv T M NsMWN mm m QQ i m 0 w ww Nb, NN M 0n NN v vh S w whJ mw/ Feb. 9, 1965 R. PRINCE HYDRAULIC CYLINDER DEVICE 2 Sheets-Sheet 2 Filed Oct. 8, 1962 United States Patent Oce lbd Patented Feb. 9, i965 3,163,353 HYDRAUMC CYLINDER DEVICE Richard Prince, lltlill S. St. Marys, Sioux City, Iowa Filed (Pct. 8, 1962, Ser. No. 228,848 6 Claims. (6l. 9ll-167) My invention relates to hydraulic cylinders and more particularly to a hydraulic cylinder wherein the stroke of the piston rod can be selectively adjusted. The ability to vary the stroke of the piston in hydraulic cylinders permits such a cylinder to be adapted to a greater variety of equipment. However, the employment of mechanical means to accomplish this result is expensive and requires time, energy, and sometimes skill on the part of the operator. ln addition, special tools are sometimes needed to complete this task.

Therefore, a principal object of my invention is to provide a hydraulic cylinder device where the stroke of the piston therein can be selectively adjusted by hydraulic power.

A further object of my invention is to provide a hydraulic cylinder device wherein the stroke of the piston therein can be selectively adjusted by the same source of hydraulic power that operates the conventional structure of the piston.

A still further object of my invention is to provide a hydraulic cylinder device wherein the stroke of the piston therein can be selectively adjusted without the use of tools.

A still further object of my invention is to provide a hydraulic cylinder device wherein the stroke of the piston therein can be selectively adjusted to a plurality of different increments.

A still further object of my invention is to provide a hydraulic cylinder device wherein the stroke of the piston therein can be selectively adjustedjfromone position to another very easily and very quickly.

A still further object of my invention is to provide a hydraulic cylinder device wherein the stroke of the piston therein can be selectively adjusted and which will not appreciably affect the size of the cylinder.

A still further object of my invention is to provide a hydraulic cylinder device wherein the stroke of the piston therein can be selectively adjusted without adversely afecting the normal functioning of the cylinder.

Still further objects of my invention are to provide a hydraulic cylinder device that is economical in manufacture, durable in use, and rened in appearance.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangements, and combination, of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specically pointed out in my claims, and illustrated in the accompanying drawing7 in which:

FlGURE l is an elongated sectional view of my device taken on line 1-1 of FIGURE 5 and shows the master piston in its position of maximum withdrawal `into the cylinder casing; A

FIGURE 2 is a sectional view of my device taken on line 2-2 of FIGURE 5 and shows the slave piston moved to an alternate position to shorten the allowable displacement of the master piston;

FIGURE 3 is a schematic view showing the hydraulic circuitry of my device;

FlGURE 4 is a sectional view of my device taken on line 4-d of FIGURE 2; and

FGURE 5 is a sectional View of my device taken ou line 5 5 of FIGURE 2.

l have used the numeral lil to generally designate a hollow cylinder casing. A rear casting l2 is` secured to the rearward open end of casing lll by weldment ld. Clevis elements l5 extend rearwardly from casting l2 to permit attachment of the entire unit to the desired supporting surface. As shown in FEGURES l and 5, a bore lil extends radially inwardly towards Ithe center of casting l2 from the outer periphery thereof to communicate with an axial bore 2li. The outer end of bore i3 is threaded and serves as a port for attachment to a hydraulic line. The rearward end of bore Ztl is threaded and receives threaded plug 22. The rearward end of bore Ztl has a greater diameter than the forward end thereof. An elongated hollow tube 2d is adapted during assembly to be inserted through bore Ztl into casing lil. The rearward end of tube Zd is ilared adjacent shoulder 2d in bore 2l), and tube 2d is also flared at 28 adjacent the forward center portion of casting l2. This structure holds tube 24 against longitudinal displacement with respect to the casting. ealing ring 25 is located in a suitable recess in casting l2 to embrace tube 2li which serves to prevent any passage of fluid through bore Ztl outside of tube 2d.

As shown in FlGURES 2 and 5, a bore 3d extends partially towards the center of casting l2 and terminates in a longitudinal bore 32 which in turn communicates with a circular well 34 on the inner face of the casting. rThe outer end of bore .lll is threaded and serves as a port for connection to a hydraulic line. A slave piston 36 is slidably mounted on the portion of tube 2d within casing itl. Sealing rings 33 and dll are mounted in suitable recesses within piston 356 to slidably seal the piston with respect to the outer surface of tube 2d and the inner surface of casing ld. An indentation 42 in the rearward face of piston Se is capable of receiving the flared portion 2S of tube 24 to enable the rearward face of the piston to engage the forward face of casting l2 as shown in FIGURE l.

A head casting lll is mounted in the forward open end of casing fill by means of oval ring du which is positioned in registering slots in the casting and casing according to the teachings of my earlier Patent No. 2,899,917 issued .lune i6, 1959. Sealing ring d is received in a suitable recess in casting dal to ei'ect a seal between the casting and the casing lu. A hollow piston rod Sil slidably extends inwardly through a center bore 52 in casting dd, and a master piston 5ft is threadably secured to the inner or rearward end thereof within casing ld'. Tube 2d is of such length and of such diameter that at least a portion ot its length will always extend into rod dll. Tube 24 has a reduced diameter which leaves an open space between its outside surface and the inside surface of rod Eil. Sealing rings 56 and 5d appear in suitable recesses in casting id and piston Sil, respectively, to prevent the passage of hydraulic iiuid between these elements and tube 2li. The rearward end ell of bore 52 is enlarged in diameter and communicates with a radial bore dit in casting d4 which is threaded at its outer end and registers with an aperture in casing lli to serve as a port for connection to a hydraulic line. Circular wells de and d6 appear in opposite faces of piston 5d, and radial conduits 63 in the rearward face of the piston connect well 66 with the interior ot piston rod Sil. Conventional clevis elements d are secured to the outer end of rod SG.

In FIGURE 3, I have shown the schematic hydraulic circuit whereby my device is operated. A motor 72 is connected in conventional manner to hydraulic pump 74. Hydraulic line 76 extends from pump 74 to hydraulic reservoir 78, and line titl extends from the pump to one side 0f conventional three-position hydraulic valve S2, which is operated by lever 84. Lever ttf-lnormally is held in a neutral or closed position. Line 35 connects valve 82 with a conventional two-position valve SS which areas is operated by lever gti. Lever 9d is normally held in one of two open positions as will be described hereafter. Lines 92 and 9d connect valve d8 with bores or ports itl and Sil, respectively, in rear casting llZ. Line 96 connects valve SZ' with bore or port 62 in head casting 4d, an line 98 connects valve d2 with reservoir 78.

yThe normal operation of my device is as follows: With the master piston 54 and slave piston 36 in the positions shown in FIGURE l, the master piston is permitted its maximum displacement within casing itl. Thus, when motor 72 is energized to cause pump '7d to deliver fluid under pressure from reservoir 7S to valve S2, lever 84 thereon can be moved to the right as viewed in FlGURE 3 to allow the fluid to move into or against the iluid in line 86. Valve 88 is normally open to allow fluid to immediately pass from line into line 92. Fluid thereupon enters into bore 1S of casting l2, and thence forwardly and out the forward end of tube 24 into the interior of a piston rod t?. The fluid thereupon moves rearwardly inside rod Sil and outside tube 24, and thence moves forwardly against the rear face of the master piston 54 by passing through conduits 68 and into the well 66 on the rear face of the piston. This causes the piston 5d and rod 5t) to move forwardly in casing it), and the fluid forwardly of the piston is forced out bore d2 into line 96, back through valve 82, and thence through line 98 to reservoir 78. As the position of lever Sd is moved to the left, as viewed in FlGURE 3, the fluid under pressure is diverted from line Si) to line 96 and the llow of uid within casing it) as described above is reversed as piston 5d is moved rearwardly in the casing. Fluid then being exhausted from the lines 92 and S6 is diverted through valve 82 back to reservoir 78 through line 9%. The above procedure governs the normal use of the master piston 54.

When it is desired to change the stroke of rod Si) and piston 54, the piston 54 is moved adjacent the slave piston 3e as shown in FlGURE l. The lever 9i? on valve 88 is moved to the right as viewed in FIGURE 3 and lever 84 on valve 82 is similarly moved to cause iiuid under pressure to enter line 94, conduits i8 and 32, and thence to move into well 3d in casting l2 to move forwardly against the rearward surface of slave piston 36. This pressure causes both pistons 36 and 54 to move forwardly in casing lil, and the fluid forwardly of piston 54 is exhausted in the manner described above. When the slave piston 36 has been moved forwardly the desired distance in casing l0, such as is shown in FIGURE 2, the lever 9d is allowed to resume its initial position which will divert pressure flow towards the cylinder through line 92 instead of line 94. This will exert pressure against the rearward side of master piston 54 in the usual manner discussed above, and slave piston 36 will then be stationary because the uid therebehind will become static. However, the captive iiuid behind slave piston 36 will prevent any rearward movement of this piston, so the master piston can be freely moved between the extreme positions defined by the rearward surface of casting 44 and the forward surface of the slave piston 36. By causing master piston 54 to move rearwardly in the manner described, and by moving lever 9i) to the right as viewed in FGURE 3, the uid behind slave piston 36 can be exhausted and the slave piston will move rearwardly. This is normally done at a time when the two pistons are in engagement with each other.

Thus, it is seen that my device accomplishes at least all of its stated objectives, and specifically provides for the selective stroke adjustment of a hydraulic cylinder by a remote hydraulic control means.

Some changes may be made in the construction and 4f arrangement of my hydraulic cylinder device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included Within their scope.

d I claim: l. In a hydraulic cylinder, an elongated hollow casing, an elongated hollow tube mounted on the longitudinal axis of said casing and extending into said casing from one end thereof, a slave piston slidably mounted on said tube, a hollow piston rod slidably extending through the other end of said casing, a master piston rigidly secured to the inner end of said piston rod,

the outer diameter of said tube being less than the inner diameter of said piston rod so that said rod can movably receive said tube,

a iirst hydraulic port in said one end of said casing in communication with the interior of said casing adjacent one side of said slave piston,

a second hydraulic port in said casing in communication with said tube,

a third hydraulic port in said other end of said casing and in communication with the interior of said casing,

a bore in one end of said casing,

a shoulder in said bore,

said tube extending partially into said bore in said one end of said casing and terminating adjacent said shoulder in said bore, said tube being flared adjacent said shoulder to prevent movement of the tube with respect to said casing,

said tube being iiared adjacent the inner end of said bore to prevent movement of the tube with respect to said casing in a direction opposite to said first direction,

and a detachable plug in the outer end of said bore, the outer end of said bore having a greater diameter than the diameter of said tube.

2. The structure of claim l wherein an indented well portion appears on the inner face of said one end of said casing, said well portion being in communication with said first hydraulic port.

3. The structure of claim 1 wherein an indented well portion appears in the face of said master piston ad-V jacent said `slave piston, said well portion being in communication with the interior of said piston rod.

4. The structure of claim l wherein an indented well portion appears on the inner face of said one end of said casing, said well portion being in communication with said rst hydraulic port, and a second well portions appears in the face of said master piston adjacent said slave piston, said second well portion being in communication with the interior of said piston rod.

5. In a hydraulic cylinder,

an elongated hollow casing,

an elongated hollow tube mounted on the longitudinal axis of said casing end extending into said casing from one end thereof,

a slave piston slidably mounted on said tube,

a'hollow piston rod slidably extending through the other end of said casing,

a master piston rigidly secured to the inner end of said piston rod,

the outer diameter of said tube being less than the inner diameter of said piston rod so that said rod can movably receive said tube,

a first hydraulic port in said one end of said casing in communication with the interior of said casing atjacent one side of said slave piston,

a second hydraulic port in said casing in communication with said tube,

a third hydraulic port in said other end of said casing and in communication with the interior of said casing,

a source of hydraulic power,

a hydraulic circuit interconnecting said source of hy- `draulic power and said first, second and third ports,

control means in said hydraulic circuit to selectively 6. The structure of claim 5 wherein said alternate consupply hydraulic uid under pressure to either said trol means includes a two position hydraulic valve, a

Y second or third ports, and control element on said two position hydraulic valve noralternate control means in said hydraulic circuit to dimally directing hydraulic uid for passage through said vert hydraulic fluid from said second port t0 said 5 second port.

first port, said control means including a three position hydraulic References Cited by the Examiner valve, means connecting said valve to said source UNITED STATES PATENTS of hydraulic power, means connecting said valve to said third port and said alternate control means, 10 Igackney t"1 a control element on said valve capable of diverting ensmore e a hydraulic uid under pressure to said third port, FOREIGN PATENTS said alternate control means to preclude the passage 425,879 3 /26 Germany of fluid through the valve, said control element being normally in a position to preclude the passage 15 FRED E' ENGELTHALER Primary Examine of uid through said valve. SAMUEL LEVINE, Examiner. 

1. IN A HYDRAULIC CYLINDER, AN ELONGATED HOLLOW CASING, AN ELONGATED HOLLOW TUBE MOUNTED ON THE LONGITUDINAL AXIS OF SAID CASING AND EXTENDING INTO SAID CASING FROM ONE END THEREOF, A SLAVE PISTON SLIDABLY MOUNTED ON SAID TUBE, A HOLLOW PISTON ROD SLIDABLY EXTENDING THROUGH THE OTHER END OF SAID CASING A MASTER PISTON RIGIDLY SECURED TO THE INNER END OF SAID PISTON ROD, THE OUTER DIAMETER OF SAID TUBE BEING LESS THAN THE INNER DIAMETER OF SAID PISTON ROD SO THAT SAID ROD CAN MOVABLY RECEIVER SAID TUBE, A FIRST HYDRAULIC PORT IN SAID ONE END OF SAID CASING IN COMMUNICATION WITH THE INTERIOR OF SAID CASING ADJACENT ONE SIDE OF SAID SLAVE PISTON, A SECOND HYDRAULIC PORT IN SAID CASING IN COMMUNICATION WITH SAID TUBE, A THIRD HYDRAULIC PORT IN SAID OTHER END OF SAID CASING AND IN COMMUNICATION WITH THE INTERIOR OF SAID CASING, A BORE IN ONE END OF SAID CASING, A SHOULDER IN SAID BORE, SAID TUBE EXTENDING PARTIALLY INTO SAID BORE IN SAID ONE END OF SAID CASING AND TERMINATING ADJACENT SAID SHOULDER IN SAID BORE, SAID TUBE BEING FLARED ADJACENT SAID SHOULDER TO PREVENT MOVEMENT OF THE TUBE WITH RESPECT TO SAID CASING, SAID TUBE BEING FLARED ADJACENT THE INNER END OF SAID BORE TO PREVENT MOVEMENT OF THE TUBE WITH RESPECT TO SAID CASING IN A DIRECTION OPPOSITE TO SAID FIRST DIRECTION, AND A DETACHABLE PLUG IN THE OUTER END OF SAID BORE, THE OUTER END OF SAID BORE HAVING A GREATER DIAMETER THAN THE DIAMETER OF SAID TUBE. 